Folding of web or sheet material (e.g., paper, napkins, paper towels, tissue, etc.) is frequently performed using a pair of folding rolls that have interacting mechanical gripper and tucker assemblies. The gripper and tucker assemblies are uniformly spaced around a circumference of each respective folding roll to interact with one another so as to interfold the sheets of material. The tucker assemblies on one roll interact with the gripper assemblies of the adjacent roll, and vice versa, to alternately grip and tuck successive sheets of material fed between the rolls. As the rolls rotate, the gripper assemblies carry and release the folded sheets of material to create a zigzagged interfolded stack of sheets. The folding rolls rotate in a specified timed or phased manner to provide the desired function of folding the sheets at a desired location so as to create the zigzag interfolded stack of sheets, and to ensure that the grippers and tuckers engage the sheet and each other in a desired position. In order to adjust the timing or phasing between the rolls, the interfolding machine is stopped and an operator rotates one of the folding rolls to adjust its position relative to the other, to provide the desired phasing between the rolls.
The folding rolls of known interfolding machines are normally gear driven from a drive system that also drives other components of the machine. The phasing between the folding rolls controls the location of the fold in the sheet, as well as the position of engagement between the grippers and tuckers of the folding rolls. In order to adjust the phasing between the folding rolls, it is necessary for an operator to stop operation of the machine and to rotate one of the folding rolls by loosening bolts affixing a hub keyed to the drive input journal of the folding roll. The hub is slotted so the folding rolls can be manually rotated.
However, known folding machinery has several drawbacks. For example, known folding machinery requires that adjustments be made to the phasing of the gear drives of the folding rolls in order to provide the fold crease in the desired location on the sheet and to adjust the relative positions of the folding rolls. These phasing adjustments require the operator to shutdown the machinery, disassemble the gear drives, and make adjustments on a trial and error basis. These adjustments are costly, cumbersome and time consuming.